Ignition system.



c. F. KETTERING.

IGNITION SYSTEM.

APPLICATION FILED NOV. 3, 1910.

memed Jan. 18, 1916' .v v, Zz vZw Wi uai J, p

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GHABLES F. KETTERING, 0F DAYTGN, OHIO, ASfiIGNDE T0 THE DAYTON ENGINEERING LABORATORIES ('30., A CQRPORATION OF OHIO.

IGNITION sYs'riiM.

Specification of Letters Patent.

Patented Jan. to, 191%.

To all whom it may concern tive currents which may arise in the secondary circuits adjacent to the circuit of the cylinder ready to fire, where the sparking impulses are produced by a series of adjacent spark coils.

It has heretofore been proposed to prevent inductive currentsfrom passing from one such coil to another, by the interposition of magnetic shields.

The present invention dispenses entirely with the need oi any such devices for obstructing the passage of the ind uctivc influence to the adjacent circuit. The free pas- Sage of any such influence from one coil to its adjacent coil is entirely permitted, but the efi'ect is eliminated by dissipating any such inductive current in case it should arise.

With these and incidental objects in view, the invention consists in certain novel constructions and arrangements, a preferred form of which is shown in the drawings :10-

companying this specification.

In the drawings Figure l is a diagrammatic view of the circuits connected with Figs. 2 and 3 are de tail views of the timer or make and break device which successively breaks the current in the respective primary coils and thereby cause the successive sparking in the second ary circuits. Figs. ,4: and 5 are detail views of the make and break part of said timer.

In Fig. 1 the battery 20 is groundedion one side by the wire or conductor 21. and the other side is connected by wire 22 to the various induction cells which may be of the vibrating type as presently described. Each of these coils con'iprises primary coil 22-3, wound upon a core 24 and connected by the wire 25 to the make and break armature 26.. lhis armature 26 normally closes contact at the point 27, to close the battery circuit through the. common wire 28. The secondary coil 30 is likewise wound on the core 24 and is grounded at 31. to the primary circuit, and at the other end is connected to the spark plug 32 which is grounded in a well known manner.

The lower end of the primary coil 23 is connected by a wire 33 to a switch lever 34, the exactconstruction of which in the actual apparatus will presently be described. This switch lever 3i normally makes contact with the contact point 35 connected by wire 36 to a common short-cirmiiting wire 37. When however the switch lever "l.- is wung over to dotted line position, shown for the left hand coil in Fig. 1, itmakes contact with another contact point edwhich is grounded by a common ground wire 41.

It will be seen. that the construction of each of the vibrating, coils is similar to that just described, being); connected by the wire 28, the common short-circuit wire 37, and the common ground wire 4-1. Condensers 50 are shunted around the make and break point 27 in a well known manner. In the operation of these devices the timer is so arranged that in rotating it operates in turn' upon the four switch arms 3%, moving said arms in turn to the dotted line position of Fig. 1. When. for example, the switch-arm 3i for the left hand coil is moved into con tact with the point 40, as shown in Fig. 1 the result is that the battery current flows through the wire 22, common wire 28. contact point 27. armature 26, wire 25, primary coil 23;, wire 33, switchbi, contact point 40 and common ground wire 41, thus completing the battery circuit through the first primary coil. When the switch 34 of this coilis moved to its dotted line position, all'th'e other switches of the three remaining coils remain in the full line position with the pri mary windings of said coils short-circuited. upon thcmselves. The timer having oper--x ated the switch 34 in this manner, the pri mary coil 23 is then energized and the arma- I J ture 26 caused to vibrate 111 the usual manwhen, for example, the switch 31 of the first coil is in dotted line position so as to energize its primary and secondary 30, the switches 34 of the adjacent coils stand resting in contact with their points 35. The result of this is that all of the other primary coils although open circuited are nevertheless short-circuited upon themselves. That is, there is a complete circuit through the common wire 28, armature 26, coil 23, wire 33, point 35, and common wire 37. Therefore if when the spark occurs in the first coil, there were any inductive influence arising in the adjacent coil, any such inductive current would be dissipated by reason of the fact that the primary of the adjacent coil is sho'rtcircuited in this manner. result of this is to prevent. premature sparking in the cylinder adjacent to the cylinder ready for firing an d thus to prevent the ill effects arising from this cause.

A desirable form of timer to effect the control of the switch arms 34: in the manner described, is illustrated in Figs. 2 and 3. The cylindrical and hollow casing 60 has journaled in it the rotary timer shaft 61 carrying the rotary arm 62. Attached to the sides of the casing 60 are four binding posts 63 to which are attached the ends of the aforesaid wires 33 referred to in diagrammatic Fig. 1. These wires are the lead wires from the respective primary coils. The inner ends of these binding posts 63 are connected to the metal arms M which corre' spond to the switch arms 34: referred to in connection with Fig. 1. There are four of these switch arms Si for the four primary coil wires 33, and they normally stand pressing upward under their spring tension against the contact pins corresponding to the contact points of Fig. 1. These pins 35 are seated in the metal cap (ll which is thus electrically connected to "the binding post 65 to which is attached the lead wire 3? constituting the common short-circuiting wire referred to in connection with Fig. 1. Thus all of the switch arms 3i would normally stand making contact with the pins and thus short-circuiting the primary coils. The rotary contact arm 62 however breaks the contact betwon the arm 34 and pin in turn in the manner now described. T he outer end of this arm, as shown in Fig. l, is made with an insulating portion and a conducting portion 71, the insulating portion preceding the other in direction of rotation as shown by the arrow in Fig. l. The conducting portion 71 is of course connect ed to the main metal portion of the rotating arm 62 and thereby grounded to the framework of the engine. This corresponds to the grounding Wire 11 of diagrammatic Fig. 1.

Thus when the rotary arm 62 revolves, the insulating portion 70 first strikes the switch The icence arm 3-tl and moves it to break contact as shown at the left in Fig. 3, and then the conducting portion 71 slides into contact with the strip 31-, thus connecting said strip with the arm (32 and grounding the same. This corresponds to shifting of the switch 34 to dotted line position, shown in Fig. 1, the breaking of the contact at the point 35 occurring before the grounding of the circuit.

From the above, it will be seen that as the arm 62 revolves, it establishes the circuit from the battery 20 to each of the four primary coils in succession, by successively 1noving the switch elements 3% from the points 35, and immediately thereafter establishing a ground connection therewith.- As the bat tery current flows through each primary, the armature 26 vibrates in the usual manner, thereby permitting a succession of can rent impulses to traverse the primary wind ing. During this action, the short circuit around said primary is open.

The high tension impulses in the second ary circuits are induced in the usual mane ner.

The impulses in the primary tend to induce alternating current surges in the primary, and particularly in the secondary wintiings of the adjacent coils. All of said coils, however, are short-circuited upon themselves. As a result of this as the induced current in any secondary circuit or coil tends to build up, a magnetic field tends to establish itself through the core, which field induces current in the primary windin which latter current builds up slowly, due to selfinduction, thereby in turn exerting a retarding etlect on the magnetic field of the core. This in turn retards the secondary current to such a degree that instead of building up instantaneously to cause a dis ruptive (lls'Chui 'e at the contacts, said induced current s retarded and never attains a suiiicicntly lug. \llage to break down the air gap. The en rgy is thus dissipated witlr out firing the adjacent cylinder.

The ends of the switch arms 3-1 are prel erably beveled or rounded, as shown in Figs. 3 and 5, in order that the ends of the rotat ing contact arm may easily ride over and depress the strip.

While the form of mechanism shown herein is "well adapted to accomplish the purposes sought, it is to be understood that this is merely a preferred form of embodiment of the invention and that other forms might be adopted all coming within the scope of" the claims which follow.

What is claimed is as follows:

1. In an ignition system, the combination with a plurality of induction coils including iron. cores, primary and secondary coils and circuits, spark terminals in the secondary circuits and a main source of current for the primaries; of means for normally short-circuiting each of said primary coils to dampen any current induced in the secondary coils; and means for successively breaking the short circuit of each primary and concomitantly connecting that primary with the main source of current whereby to energize that primary and prevent any dampening effect therein.

2. In an ignition system, the combination with a plurality of inductioncoils including iron cores, primary and secondary coils and circuits, spark terminals in the secondary circuits and a main source of current for the primaries; of switch mechanism and connections for said primaries normally short-circuiting the same to dissipate any current induced in the secondary coils; and a. common member for engaging said switch mechanism and constructed to break the shortci.rciiit of each primary in turn and at the same time cornect that primary with the main source of currentwhereby sparking impulses will be induced in the secondary circuit of the said primary.

In an ignition system, the combination with a plurality of induction coils including primary and secondary coils and circuits, spark terminals in the secondary circuits and a main source of current for the primaries; of a switch and connections for each of said primaries normally short-circuiting the same, said switches being located in proximity to each other; a rotary controlling member rotating in the range of all of said switches; an insulated arm connected with said rotary member and positioned to engage said switches and break said short circuits in turn; and a conducting arm adjacent to said insulated arm and connected with said rotary member, said conducting arm being electrically connected with said main source of current and positioned to engage the switches and connect the same with said main source of current.

4. In an ignition system, the combination with a plurality of induction coils including iron cores, primary and secondary coils and circuits, spark terminals in the secondary circuits;-of a main source of current for the primaries; of means for preventing premature sparking in the cylinders, including de-' vices for normally short-circuiting said primaries and adapted to dampen the building up of induced currents in the secondary coils.

5. In an ignition system, the combination with a plurality of induction coils including primary and secondary coils and circuits,"

sparking terminals in the secondary circuits and a main source of current for the primaries; of switches and connections for member rotating in the range of all of said switches, having an arm comprising an insulated portion, provided with a beveled approach to facilitate the engagement/of the switches; and a conducting portion tor concomitantly establishing the main circuit through the switches.

6. In an ignition system, the combination with a plurality of induction coils, including primary'and secondary coils and circuits, sparking terminals in the secondary circuits; and amain source of current for the primaries; of switches each including a movable depending pin; cooperating contact strips norma lg in engagementwith said contact pins or normally short-circuiting the primary circuits; a rotary controllin member rotating in the range of all of said switches, including an arm having an insulated portion adapted to initially engage said depending pins successively and to separate them from their contact position with their normal cooperating contact strips and means for concomitantly establishing a main circuit through the switches as the normal contacts. thereof, are successively broken.

7. In an ignition system, the combination with a plurality of-induction coils having primary and secondary windings, of a main source of current for the primaries, means normally open-circuiting each primary winding and maintaining a closed circuit about the same, and means for successively establishing the circuit of said primaries andconcomitantly opening said closed circuit whereby as each primary winding is energized the remaining primary windings act as dampening devices to retard the establishment of high potential-induction currents in the corresponding secondaries.

In testimony whereof I afiix my signature in the presence of two subscribing witnesses.

CHARLES F. KETTERING.

Witnesses:

J. B. HAYWARD, CHAS. R. GILLIES. 

